Detainees set fire to Australia immigration center

April 21, 2011 12:24:03 AM PDT

SYDNEY --

Detainees at an Australian immigration detention center rioted, setting fire to several buildings, while officials scrambled to end the protest.

Officials say up to 100 detainees were involved in the riot at Sydney's Villawood Detention Center that began Wednesday night. They climbed on rooftops and threw tiles at workers who were trying to end the melee.

Flames gutted nine buildings before the fire was brought under control.

Many of the detainees are seeking asylum in Australia. Others have overstayed their visas. Officials say they don't know what sparked the protest.

On Thursday, seven detainees remained on the roof of one of the complex's buildings, next to a large sign that read: "We need help."

No one was hurt.

Immigration department spokesman Sandi Logan said officials would not negotiate with the protesters until they came down off the roof. Criminal charges could be filed against the rioters.